Retain struct when using alias this and passing using the alias..?

[simendsjo]

import std.exception;
import std.traits;

struct Ranged(T, T min, T max) {
     T _value = min;
     typeof(this) opAssign(V : T)(V value) {
         enforce(value >= min);
         enforce(value <= max);
         _value = value;
         return this;
     }
     alias _value this;
}

void f(int i) {
     i = 1000;
}

void g(T)(T i) if(isIntegral!T){
     i = 1000;
}

void main() {
     Ranged!(int, 10, 20) v;
     v = 10; // ok
     v = 20; // ok
     f(v); // auch
     g(v); // ok, exception
}

Is there a way to ensure the struct is used in f() without using templates  
as in g()?